Sighting system for guns



Se t. 10, 1935. I J, c KARNES 2,013,656 I SIGHT ING SYSTEM FOR GUNSFiled Jan. 31, 1951 3 Sheets-Sheet 1 k/fl ia f ATTORNEYS. 1

Sept. 10, 935; J. c. KARNES 2,]l3,656

SIGHTING SYSTEM FOR GUNS Filed Jan. 51, 1951 5 Sheets-Sheet 2 imuuml t Bh 0 O 1 I 7 {4 N I g k J I Q a? m I f I INVENTOR.

E d. E K arnas TTORNEY Patented Sept. 10, 1935 was . 11 Claims.

(Granted under the act of March 3, 1883, as'

amended April 30, 1928; 370 0. G. 757) The invention described hereinmay be manufactured and used by or for the Government for governmentalpurposes, without the payment to me of any royalty thereon.

The subject of thisinvention is a sighting system for guns.

Guns designed for firing against aerial. targets are distinguished fromguns employed primarily against ground targets by the character of thesighting system, by their weight and degree of mobility, and by theirmethods of emplacement. The trend .of development in light fieldartillery guns is tomodify them sufficiently to make it possible forthem to engage aerial targets. Alterations directed to this end,however, are not permitted to interfere with such essentialcharacteristics as are specified for a gun whose normal assignment isthe ground target.

One of the principal considerations encountered in the design of a dualpurpose gun mount is the factor of Weight. The present invention dealswith this phase of the problem insofar as it concerns the mechanismswhich must be provided to insure the correct laying or pointing of thegun irrespective of the level of the gun mount.

In laying a gun at a moving target it is necessary to give the axis ofthe gun barrel a position which takes into consideration, in addition torange, vertical and lateral defiection corrections caused by travel ofthe target during the dead time of loading and the time of flight of theprojectile, and also similar corrections to allow for errors caused byreason of elevating the gun on an inclined plane when the gun istransversely and longitudinally out of level due to the nature of itsemplacement.

According to the present invention it is proposed to make provision forentering the necessary corrections due to out of level position, solelyin the sighting system and to consolidate the values corresponding tothe corrections with the principal values of azimuth and elevation.

A practical embodiment of the invention is illustrated in theaccompanying drawings, wherein:

Fig. 1 is a more or less diagrammatic illustration in the nature of aView in left side elevation of a gunmount showing the generalarrangement of the azimuth component of the sighting system;

Fig. 2 is a similar view of the right or elevation side of the gunmount;

Fig. 3 is a longitudinal sectional view through the sight mount;

Fig. 4 is a transverse sectional view through the sight mount;

. Fig. 5 is a detail sectional view on the line 55 of Fig. 3;

Fig. 6 is a transverse sectional View through 5 the range drum;

Fig. 7 is a view in rear end elevation of the range drum;

Fig. 8 is a detail. sectional view showing the mounting of the pointeron the range drum;

Fig. 9 is a detail sectional View on the line 99 of Fig. 5; and

Fig. 10 is a detail view of the azimuth recorder.

Referring to the drawings by characters of reference:

In Figs. 1 and 2 there are shown the side plates 5 of a gun carriagewhich is adapted to be rotated about a vertical pivot by a traversinghandwheel 6 for the purpose of training the gun in azimuth. A cradle lwhich is adapted to reciprocally carry the usual gun barrel, issupported by the side plates through the trunnions 8 and rotated bymeans of the elevating handwheel 9.

Referring to Fig. 4, a support shaft Ill is secured to the left handtrunnion 8 and terminally carries a pin H which constitutes the axis ofcross level of the mount and is parallel to the axis of bore of the gun.Mounted on the pin is an annular bearing member 12 embraced by anannular sight mount l3 that is rotatable with respect to the bearingmember. The upper portion of the sight mount is formed with a socket I4for receiving an adapter l5 which supports a telescopicsightinginstrument I6. The adapter is movable with respect to the sightmount by 5 means of the gearing I5a.

The lower portion of the sight mount pivotally carries a Worm wheelsector I1 mounted to slidein a block l8 secured to an arm l9a of arocker l9 journaled on the support shaft Ill. The block I8 also carriesa shaft 20 having a worm 20a in meshwith the sector I! and serving tomove the sight mount about the axis of cross level I I. A spirit level2! placed transversely of the sight mount 13 is provided for indicatingthe level position of the sight mount.

The rocker l9 carries an arcuate housing 22 in which a segment 23 isslidably mounted. A pointer 24 on the segment is arranged to registerwith a reference mark 25 on the sight mount IS. A shaft 26 in thehousing 22 has a worm 21 meshing with the segment 23 and a worm 28meshing with a worm wheel on an inclined shaft 29 also mounted in thehousing 22. A flexible shaft 30 on the shaft 29 leads to a set ofdifferential geardrum 48.

ing 3| (Fig. 1) into which is introduced a shaft 32 associated with theazimuth mechanism 6 and affording a measure of the azimuth of the guncarriage. transmitted by a shaft 33 to a register 34 where it isinterpreted in movement of a pointer 35 (Fig. 10) which is comparablewith a second pointer 36 actuated from a remote control station andexpressing the value of azimuth from level datum to the position of thetarget.

Referring to Figs. 3 and 4, the rocker l9 is formed with an arcuate rack31 meshing with an operating shaft 38 carried in a bracket 39 secured tothe side plate 5 of the carriage. This mechanism is provided for thepurpose of shifting the sight mount as an entity through a longitudinalangle to compensate for subsidence of the carriage or lack of fore andaft level. In order to indicate when the sight mount is levelledlongitudinally there is provided a spirit level 40 on the upperextremity of the rocker I9.

Referring to Figs. 6 and 7 a hollow support shaft 4| secured to theright hand trunnion is formed with an arm 4|a in which is mounted aplanet pinion 42. This pinion meshes internally with a drum 43 mountedon the support shaft 4| and normally locked against movement throughagear segment 430. which is in mesh With a worm shaft 44 carried in abracket.45 (Fig. 2) fixed to the side plate.

The pinion 42 is also in mesh with a sun gear 46 on a shaft 4'! mountedwithin the hollow supthe drum 43 and serving to lock these two memberstogether as well as provide for relative angular displacement.- The bandhas a laterally projecting finger 53 inscribed with a reference mark 54readable against the range scale 49 on the drum 48 and it also has areference pointer 55 readable against a mil scale 56 on the drum 43.

The band also carries a laterally projecting arm 57 terminating in acasing 58 overlying the Journaled in the casing is a drive shaft 59 anda driven shaft 60, the engagement being preferably through worm gearing.A pointer 6! secured to the driven shaft and readable against the rangescale 56 is equipped with a transversely disposed spirit level 62. V

The graduations of the range scale are in the form of curves plotted infunction of elevation and angle of cross level and varying fromconcentricity with the pointer 6| by amounts proportionate to theelevation error due to elevating on an inclined plane.

The reference mark 54 and the pointers and 6| are all carried by theband 5| and are displaceable when the band is moved independently of orin conjunction with the drum 43. In order to indicate when the drum 43is levelled longitudinally it is provided with a spirit level 63 (Fi 7)As shown in Fig. 2 a register 64 is mounted on the side plate of the guncarriage and has a pointer 65 actuated from a remote control station andindicating the value of elevation at which the gun is .to be pointed indirect or indirect firing. p

In practice, a gun carriage when emplaced is seldom level transverselyand longitudinally, due

The production of the differential is pointer 6| of the range drum unitis levelled transversely by operating the shaft 59. In these operationsspirit levels 2|, 46, 63, and 62 are referred to.

The axis of cross level ll of the sight mount being parallel to the axisof bore of the gun and being movable in elevation with the gun trunnionwill indicate the angle of elevation of the gun.

As may be seen from Fig. 4 when the gun carriage is transversely level,the sight mount will be in a true vertical plane perpendicular to thesupport shaft H) and there will be no effect on the sight mount when theaxis of cross level I! is angularly displaced during elevation of thegun.

When the gun carriage is not transversely level, the sight mount uponbeing cross leveled to position it in a true vertical plane, will nolonger be perpendicular to the support shaft l6. As a consequence,angular displacement of the axis of 7 cross level II during elevation ofthe gun will force the sight mounting to revolve about an axis which isthe pivot of the worm wheel sector IT. The sighting instrument carriedby the sight mount is thereby automatically deflected an amount equal tothe error in azimuth which results by reason of elevating the gun on aninclined plane. The gun is then traversed torelay the sightinginstrument on the target or aiming point.

The rocker on being levelled longitudinally angularly displaces thesight mount relative to the support shaft. This has the eifect ofentering an elevation angle but is compensated for as will be explainedlater in connection with the range drum unit. In the case ofanti-aircraft firing, the amount of deflection or azimuth error isinterpreted by the displacement of the reference mark 25 on the sightmount with respect to the pointer 24 carried by the segment 23.Operation of the inclined shaft 29 to move the pointer 24 into registerwith the reference mark 25 affords a measure of the lateral deflectioncorrection and is transmitted to the differential 3| for combinationwith the principal angle of azimuth. The azimuth operator turns thetraversing handwheel 6 to keep the pointer 35 matched with the pointer36 whose position is controlled from a remote station and represents thefinal value of azimuth based on level datum. V

The elevation component of the error caused by reason of elevating thegun on an inclined plane is compensated for in the curves of the rangescale 50. When the pointer 6| is transversely levelled the amount ofelevation of the gun and consequent rotation of the drum necessary toregister a prescribed range curve with the pointer will be greater asthe angle of cross level increases.

The initial adjustment of the range drum unit by longitudinallylevelling the drum 43 has the effect of angularly displacing the band 5|carrying the reference mark 54 and the pointer 6| and also displacingthe drum 43 as previously explained to place it in the horizontal datumplane. Angle of site displacement is made by moving'the moves on aninclined plane. level 62 has been properly leveled, the rotation bandthrough the shaft 52 to further displace the reference mark 54 andpointer 6!, this displacement being read on scale 56. The amount ofrotation of the gun and range scale 5!] in order to register aprescribed range curve for example with the pointer 6| will be greateror less, depending on the angleof site and-the character of thelongitudinal inclination of the gun carriage.

The amount of this correction is not required in the sight mounting butbecause it is represented in the ultimate inclination of the axis ofcross level II by virtue of the interdependence of the two guntrunnions, it was necessary to longitudinally level the rocker anddisplace the sight mount relative to the axis of cross level in order toneutralize the angular displacement of the axis of cross levelintroduced by operation of the range drum unit.

Since the gun containing the axis of bore is mounted by means of twotrunnions it is obvious that all displacements of the trunnions. arereflected in the position of the axis of bore. If the gun is rotated inazimuth while out of level it When the spirit of the gun in azimuth onan inclined plane will soon throw it out of level, so that inconsequence, when elevation is to be applied, the pointer 6| must beacted on to restore it to a level position.

Since the azimuth movement includes the correction in azimuth(242229-3I) due to tra versing on an inclined plane, this correctionwill also be reflected in the resulting elevation error. In view of thisthere is exceptionally close cooperation between the pointer 24, thetraversing mechanism 6 and 3! and the pointer 6|. Con- Versely, if thegun is elevated on an inclined plane there will be an error in elevationand also in azimuth. Elevation through 9 in an amount controlled orindicated by the mechanism of Fig. '7 rotates the trunnion on the leftside of the gun and displaces the reference 25 (Fig. 3) to measurablyindicate the azimuth error which must be applied through 30 to 3|.

It will be noted that the range scale 49 does not take into account theerror in elevation caused by elevating on an inclined plane. Undercertain conditions the field artillery disregard this error but if it isdesired to take this error into account the gun is laid by employing thescale 50.

All elements of the sighting system may be employed irrespective of thecharacter of employment of the gun. When azimuth and elevation data arenot supplied from a remote station and continuously and automaticallyrecorded in the vicinity of the sighting system then these directionalvalues are applied in the customary manner. In firing at a moving groundtarget, lateral deflection corresponding to the lateral movement of thetarget may be set in by moving the adapter I5 through the gearing 1511.

I claim:

1. In a sighting system for guns, a carriage, means for traversing thecarriage, a register indicating computed azimuth data, means fortransmitting the traversing movement to the register for comparison withthe computed data, a gun cradle 'trunnioned in the carriage, means forelevating the cradle, a sight mount having an axis of cross level fixedparallel to the gun bore on one of the trunnions, said sight mount beingangularly displaceable with respect thereto for longitudinal levelling,means for moving the sight mount about the axis of cross-level, areference mark on the sight mount, a pointer readable against thereference mark, means for moving the pointer to align it with the mark,means actuated by said moving means and combining'the pointer movementwith the traversing movement, means 5 transmitting a measure of suchcombined movement to the register, a drum carried by the other trunnion,a chart of curves on the drum plotted in function of angle of elevationand angle of crosslevel, a band having a pointer readable against thechart of curves, means for cross-levelling the pointer, and means forangularly displacing the band to level it longitudinally.

2. In a sighting system for guns, a carriage, means for traversing thecarriage, a register indicating computed azimuth data, means including adifferential for transmitting the traversing movement to the registerfor comparison with the computed data, a gun cradle trunnioned in thecarriage, means for elevating the cradle, a sight 1 the gun is elevatedto compensate for the error in l azimuth due to elevating the cradle onan inclined plane, means for measuring such deflection and actuatingsaid diflerential to algebraically combine it with the traversingmovement for indication in the register, and means associated with atrunnion for indicating the elevation of the cradle corrected for theerror in elevation due to transverse inclination of the carriage.

3. In a sighting system for guns, a carriage, means for traversing thecarriage, a register indicating computed azimuth data, means including adifferential for transmitting the traversing movement to the registerfor comparison. with the computed data, a gun cradle trunnioned in the40 carriage, a bearing member jointed toone of the trunnions forcross-levelling about an axis parallel to the gun bore, a sight mountcarried by the bearing member and rotatable thereon in a planecontaining or parallel to the axis of cross-level, a rocker on thetrunnion, means associated with the rocker and engaging the sight mountfor moving the sight about the axis of cross-level, a reference mark onthe sight mount, a pointer carried by the rocker, means for moving thepointer into register with the reference mark, and means fortransmitting such movement to the difierential for algebraicallycombining it with the movement of the traversing means.

4. In a sighting system for guns, a carriage, means for traversing thecarriage, a gun cradle trunnioned in the carriage, a bearing memberjointed to one of the trunnions for cross-levelling about an axisparallel to the gun bore, a si ht mount carried by the bearing memberand rotatable thereon in a plane containing or parallel to the axis ofcross-level, a rocker on the trunnion, means associated with the rockerand engaging the sight mount for moving the sight in crosslevel, areference mark on the sight mount, a 5 pointer carried by the rocker,means for moving the pointer into register with the reference mark, andmeans for algebraically combining a measure of the movement of thetraversing means and the pointer.

5. In a sighting system for guns, a carriage, means for traversing thecarriage, a register indicating computed azimuth data, means fortransmitting the traversing movement to the register for comparison withthe computed data, a gun 75 mounted in the carriage for elevation, acrosslevelling sight mount carried by the gun and arranged to bedeflected in azimuth due to trunnion tilt as the gun is elevated tocompensate for the error in azimuth, and means on the carriage formeasuring such deflection and algebraically combining it with thetraversing movement for indication in the register.

6. In a sighting system for guns, a carriage, means for traversing thecarriage, a gun mounted in the carriage for elevation, a cross-levellingsight mount carried by the gun and arranged to be deflected in azimuthdue to trunnion tilt as the gun is elevatedto compensate for the errorin azimuth,

, and means for algebraically combining and registering a measure of thetraversing movement and the deflection of the sight mount.

7. In a sighting system for guns, a rotatable support, a sight mountcarried by the support and rotatable with respect thereto,cross-levelling mechanism for the sight mount arranged to constrain thesight mount to be deflected in azimuth when the support is elevated inan inclined plane, a reference mark on the sight mount, a pointermounted independently of the sight mount, for movement in an arc andreadable against the reference mark, means for moving the pointer toalign it with the reference mark and means actuated by said moving meansfor indicating a measure of such movement.

8. In a sighting. system for guns, a support rotatable in elevation, arange drum carried by the support and rotatable with the support as itmoves in elevation, said drum bearing a chart of curves each plotted incoordinates of corrected elevation and angles of cross-level, a pointermovable in cross-level and readable against the chart of curves, meansfor angularly displacing the pointer about the drum to level itlongitudinally, a crosslevelling sight mount rotatable with respect tothe'support and arranged to be deflected in:azi-- muth when the supportis elevated in an inclined plane, and means carried by the support forangularly displacing the sight mount relative to the support to level itlongitudinally. 5

9. In a sighting system 'for guns, a support rotatable in elevation, arange drum carried by the support and rotatable with the support as itmoves in elevation, said drum bearing on its periphery a chart of curveseach plotted in coordinates of 10 corrected elevation and angles ofcross-level, a' pointer movable in cross-level and readable against thechart of curves, and means for angularly displacing the pointer aboutthe drum to level it longitudinally. V

10. In combination, means for computing data for a gun correct for alevel platform, a gun, training mechanism for moving the gun,lflr'econtrol apparatus mounted on the gun giving a corrected value of gunsetting, means for algebraical- 20,

1y combining the movements of the training mechanism and the valuedetermined by the firev control apparatus, and a register indicatingcom-' puted data for comparison with the combined movements of thetraining mechanism and fire 25;

control apparatus a 11. In agun, means for moving the gun i azimuth,means for elevating the gun, a sight mount, means associating thegun'and mount so that the latter is deflected in azimuth as the gun 30

